Controlled drug release of silicone-based adhesive-containing cross-linked siloxane powders as a reservoir

We prepared pressure-sensitive adhesive (PSA)-containing cross-linked siloxane powders (CS) as a reservoir for a transdermal drug delivery system (TDDS) and evaluated their sustained drug-release properties. PSA, as a patch-type adhesive, was synthesized by a hydrosilylation reaction of vinyl-terminated polysiloxanes with hydrogen-terminated polydimethylsiloxanes. CS was also prepared via a hydrosilylation process with vinyl-terminated polydimethylsiloxane, 1,3,5,7-tetramethyl-1,3,5,7-tetravinyltetracyclosiloxane (D4Vi), hydrogen-terminated polydimethylsiloxane, and dimethylhydrogenmethyl oligomeric siloxane copolymer. The results of release performances using ascorbic acid as a model drug showed a cumulative linear slope over a week, indicating a constant release performance. Our data suggest that this siloxane TDDS could be useful for constant drug release over a long period.